Angle Sensor System Noise Rejection via Dual-Sensor Field Ratio
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Solution Overview
Problem
Magnetic angle sensors face errors in angle detection due to noise magnetic fields, such as the earth's magnetic field and motor leakage fields, which affect the accuracy of angle detection values.
Innovation Solution
An angle sensor system utilizing two magnetic sensors and a processor to generate an angle detection value by processing detection information from both sensors, with the ratio of magnetic field strengths at different detection positions optimized to reduce noise-induced errors, featuring a magnetic structure with specific geometrical configurations to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnetic sensor is used for angle detection, then the device complexity is low, but angle detection accuracy deteriorates due to noise magnetic fields
Solution Approach 1:
The patent divides the detection function into multiple magnetic sensors positioned at different locations. Each sensor detects the magnetic field at its specific position, and the processor segments the detection information to calculate the angle while compensating for noise. This segmentation approach improves angle detection accuracy by reducing the impact of noise magnetic fields while maintaining manageable system complexity through modular sensor placement.
2Measurement precision
If multiple magnetic sensors are used to reduce noise impact, then angle detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent combines multiple magnetic sensors and their detection functions into an integrated angle sensor system. The processor merges the detection information from multiple sensors to generate a single angle detection value, consolidating the complexity of handling multiple sensors into a unified processing approach. This merging strategy improves angle detection accuracy through noise cancellation while presenting a simplified interface for angle measurement.
3Measurement precision
If magnetic sensors are placed at different positions to detect composite magnetic fields, then noise field effects are reduced, but the layout complexity increases
Solution Approach 1:
The patent applies local quality by positioning magnetic sensors at specific locations where they detect magnetic fields with different characteristics. Each sensor is placed at a position optimized for its local magnetic field environment, allowing the system to exploit spatial variations in the magnetic field to reduce noise effects. This local optimization improves angle detection accuracy while maintaining a relatively simple overall layout through strategic sensor placement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces angle errors caused by noise magnetic fields, improving the accuracy of angle detection values by using a processor to combine information from multiple sensors and optimizing magnetic field strength ratios.
Implementation Method 1
a magnetic field generator for generating a magnetic field to be detected, the direction of which rotates in response to the rotation or linear movement of an object
Implementation Method 2
Each of the plurality of detection circuits includes at least one magnetic detection element
Data Source
AI summary
A magnetic field generator generates a detection-target magnetic field related to an angle to be detected. An angle sensor includes a first and a second magnetic sensor and a processor. The first magnetic sensor detects, at a first detection position, a first applied magnetic field including the detection-target magnetic field, and generates first detection information having a correspondence with the angle to be detected. The second magnetic sensor detects, at a second detection position, a second applied magnetic field including the detection-target magnetic field, and generates second detection information having a correspondence with the angle to be detected. The processor generates an angle detection value by performing arithmetic processing using the first and second detection information. The ratio of a strength of the detection-target magnetic field at the second detection position to a strength of the detection-target magnetic field at the first detection position is 1.65 or more.